At first glance, Twitter has all the hallmarks of an internet fad. The microblogging serv ice, which limits posts to 140 characters, has become a favourite of celebrities and the restless digerati who always seem to be "discovering" some hot new thing. Britney does it and so does Lance. Barack, of course, has been at it for ages.
It comes with its own quirky language. Messages are known as tweets and people who read your messages are called "followers". Then there are the particular Twitter culture and modes of behaviour: sociability is enhanced by "retweeting" messages you find particularly illuminating - rebroadcasting them to your own followers. Among hardcore users, gratuitous selfpromotion is frowned on.
